#include <stdio.h>
#include <stdlib.h>
int main(int argc, char * argv[])
{
  if (argc < 2) 
    {
      printf("need a number\n");
      return -1;
    }
  int v = (int)strtol(argv[1], (char **)NULL, 10);
  printf("argument = %d\n", v);
  int cnt; /* a counter */
  for (cnt = 0; cnt < v; cnt += 3)
  {
  	printf("cnt = %d\n", cnt);
  }
  return 0;
}
